Clinical diagnostic analyzers with increasing levels of complexity and sophistication are being developed to perform chemical assays and immunoassays of biological fluid samples such as urine, blood serum, plasma, cerebrospinal liquids and the like, with much emphasis placed on reducing the time to obtain an initial test result and/or increasing analytical throughput. Throughput improvements, while desirable, may be hampered if corresponding advances are not made in the automation of pre-analytical sample preparation and handling operations like sorting, batch preparation, centrifugation of sample tubes to separate sample constituents, cap removal to facilitate fluid access, and the like.
Laboratory automation systems (LAS) have been developed to handle specimens (blood, urine, and body fluids) contained in standard, bar code-labeled, evacuated tubes. The bar code label contains an accession number coupled to demographic information that is entered into a hospital's Laboratory Information System (LIS) together with test orders and other desired information. An operator places the labeled tubes onto the LAS system which performs all functions automatically including sample sorting, routing, centrifugation, aliquot preparation, sample analysis at one or more analyzers, before making the tested sample available for post-analytical storage and retrieval.
Subsequent to processing, and because as many as one tenth of all processed tubes are required for additional tests or for retesting, patient samples are advantageously stored in refrigerated space and retrieved when follow-on testing is required. Automated, refrigerated storage and retrieval systems are available in either of two basic types. In one instance, the storage and retrieval systems are connected directly to the laboratory work-system and sample tubes are robotically removed from the conveyor and stored in a refrigerated unit placed nearby the LAS. Such LAS-connected storage-and-retrieval systems have disadvantages because the space nearby the work-system is often scarce or has a higher priority demand and because storage therein is limited to samples tested on the connected LAS. For these reasons, storage and retrieval systems are more typically placed in a remote location and sample tubes are placed in racks which are moved by an operator to the remote storage and retrieval system where the racks are robotically stored and retrieved when required. Tubes are typically selected by a robot, inventoried by reading the bar code, and transferred to large-capacity storage trays that are mechanically transferred into refrigerated storage; samples are also automatically discarded upon expiration of their designated storage time. Such storage and retrieval systems generally include conventional industrial inventory management operation having on-board inventory control and tracking software, and an overall system controller.
Laboratory automation systems having pre-processing capabilities are known and these generally include conveyor systems for conveying specimens to analyzers, such as those described in U.S. Pat. Nos. 6,060,022, 6,220,451, and 7,141,213, discussed below. Typical of such systems, a sample is transported to an analyzer by a primary conveyor and either removed from the primary conveyor by a robotic-like device and placed into a sampling area of an adjacent analyzer or may be shuttled onto an analyzer-specific conveyor that transports the sample to the sampling area of an adjacent analyzer. In the later instance, when sufficient sample aliquots have been removed from the sample, the sample is returned to the primary conveyor and transferred thereto from the analyzer-specific conveyor.
U.S. Pat. No. 6,742,344 discloses a shelved cupboard for refrigerated goods, comprising an opening for putting in or removing refrigerated goods and an arrangement of ducts for circulation of cooled air from an associated cooling element, such as an evaporation battery. The air that is circulated in the ducting system and the interior of the cupboard, as well as between the refrigerated goods, may be cooled to a greater or lesser degree by primary or secondary air.
U.S. Pat. No. 7,141,213 discloses a modular workstation that can automatically prepare biological specimens for further processing by a large variety of analytical equipment, without having to replace existing analytical equipment. The system can sort incoming samples, and prioritize STAT samples. As needed, incoming samples can be automatically centrifuged, decapped, and transported to selected analytical equipment. The system can be automatically controlled through the use of a central controller. The system provides efficient, high throughput and fast turnaround analytical results, with decreased chance for operator error and decreased exposure of operators to biological substances.
U.S. Pat. No. 6,060,022, automatically presents pre-processed samples in open containers to robotic devices operated in conjunction with independent stand-alone analyzers. In order to provide precise and accurate handling of the sample tubes, it is critical to position and align the tubes within a sample tube carrier accurately so that the various robotic handling devices may automatically and consistently remove or replace tubes from tube carriers as needed.
Although these prior art systems have advanced sample handling and processing throughput, existing sample storage-and-retrieval systems have the disadvantages of either requiring a large amount of laboratory space or of requiring an operator to transport and retrieve racks to and from a remote location. This is particularly disadvantageous since it has been discovered that a large number of samples required to be re-tested are initially tested on the same day that follow-on tests are ordered.